Machines of this type are known, for example from U.S. Pat. No. 3,596,999. During a first working cycle the bristle bunch holder is moved toward a bristle magazine, in which bristles which are cut to the desired length are stacked parallel to one another. The bristle holding sleeves penetrate through holes in the magazine wall and collect plural bunches of bristles. After the sleeves are pulled out, the bristle bunch holder is aligned with a melting station, in which the mutually adjacent ends of all bunches are pressed onto a heating plate and melted to simultaneously fasten together these ends. The individual bristles of the bristle bunches melt together. After the melting process, the bristle bunch holder is aligned with a brush head and the melted, still soft ends of the bunches are pressed against the brush head, which consists preferably of a thermoplastic material, whereby a fixed connection between the bristle bunches and the brush head is created. The locations on the brush head to be coupled with the bristles can be melted by heating same prior to a pressing on of the bristle bunches, for example by pressing heated pins thereagainst. This results in a particularly good bond.
In the mentioned U.S. Pat. No. 3,596,999, the various stations are provided on a rectilinearly movable carrier. However, machines are also known which have a step-by-step movable carrier, on which carrier several bristle bunch holders are provided, which are all simultaneously movable radially outwardly. During each such movement, the bristle holding sleeves of a bristle bunch holder project into the stationarily arranged bristle magazine, while at the same time a melting takes place at a different location and a welding of the bristle bunches takes place at a further location. A step-by-step rotatable magazine with several receiving means for the brush heads is provided in the welding station. The magazine moves the brush heads first in front of a melting station, in which a hot plate having pins thereon is pressed against the brush head, in order to melt the brush head to each later fastening point of a bristle bunch. The brush head is thereafter moved by the rotatable magazine in front of the bristle bunch holder, which presses the bunches onto the melted locations on the brush head. In comparison with a rectilinearly movable carrier, the performance in such an arrangement is substantially increased.
It can happen during the production of brushes that the bristle bunches are not orderly welded to a brush head. This can result in a portion or possibly also all bristles remaining in the bristle holding sleeves during a retraction of the bristle bunch holder. If now the bristle bunch holder is again to take bristles from the bristle magazine, further undesirable interference is created, because partially or fully filled bristle holding sleeves are pressed into the bristle magazine. This results in every case in a disorganization in the bristle magazine and thus in a breakdown in the bristle supply. Also bristles can become wedged or jammed in the bristle holding sleeves. To overcome such breakdowns or interference is time-consuming and as a rule is also associated with a loss of bristle material and results finally in a considerable increase in the manufacturing expense.
In the known machine with a rotatable magazine, each brush head receiving means is designated for only one brush head. After leaving the welding station, the finished brush must be manually removed. This requires alone one operator for insertion of bristle heads and for removing the finished brushes so that careful attention must be paid that a brush head which is already provided with bristles does not again move into the welding station, because this would result in an undesirable breakdown in operation.
The basic purpose of the invention is to construct a machine of the above-mentioned type in such a manner that it is assured that bristle holding sleeves which are free of bristles when they are pressed into the bristle magazine. Through a further development of the invention, a further improvement of the operating efficiency is achieved by preventing the repeated movement of a finished brush into the welding station.
The inventive machine of the above-mentioned type is characterized by a discharge station in which ejectors are pushed through the hollow bristle holding sleeves during forward movement of the bristle bunch holder.
In the inventive machine, the bristle bunch holder is emptied precautionarily by pushing ejector pins through the bristle holding sleeves. During a trouble-free operation, this ejection procedure has no importance. However, if bristles remain in the bristle holding sleeves, these are pushed out of the sleeves so that during the following pressing of the bristle holding sleeves into the bristle magazine a smooth reception of the bristle bunches is assured. This cnsiderably improves the operating efficiency of the machine. Also material losses are avoided, which are caused by a disorderly array of bristles in the bristle magazine. The performance of the machine is, as a result and as a whole, considerably improved.
A machine with four bristle bunch holders is preferable. A larger number of bristle bunch holders hardly brings about any advantages. Each bristle bunch holder is then during each working cycle of the machine in one of the four stations, of which one is the inventively provided ejector or discharge station.
Ejectors are preferably associated with each bristle bunch holder. However, embodiments also fall within the scope of the invention, in which the ejectors are stationarily arranged and engage only in the discharge station the bristle holding sleeves. This embodiment has, however, the advantage that the problem of threading of the ejectors into the bristle holding sleeves does not exist.
With the further development of the invention, one achieves a substantial further increase in the performance of the machine. Namely, it is now possible to absorb in the magazine very many brush heads so that one operator will be able to operate several machines. This is made possible also particularly by the fact that attention must no longer be paid to the timely removal of finished brushes, because these are ejected automatically.
Further special characteristics, aside from the base in the discharge station which can be retracted, one could also use different removing means. For example one could design the lower ends of the holding bars to be removable. A removable base, however, has the special advantage that the force of gravity is fully effective for the ejecting operation, so that special ejecting means are not needed.
In place of the movement device, it could also be possible to provide for example a control cam, which operates the lever.